Low-fat diets in women can reduce mortality rates of breast cancer

Results from an almost thirty-year clinical trial regarding women’s nutritional health and breast cancer were announced recently and will be presented at the annual meeting of the American Society of Clinical Oncology in Chicago. The results come from the Women’s Health Initiative and offer the first conclusions that diet – particularly, a lower-fat diet – can decrease postmenopausal women’s risk of dying from breast cancer.

Over 48,000 women across the US participated in the clinical trial from 1993-1998. During this time, they were instructed to follow either their usual diet, in which fat accounted for 32% of daily calories on average, or a lower-fat diet, in which fat was only 20% of calories. Those following the lower-fat diet also were instructed to eat daily servings of vegetables, fruit and grains. None of the participants in the trial had breast cancer upon the start of the study. The women continued this dietary intervention for 8 and a half years and received follow-up monitoring for the next twenty.

While the women maintaining the lower-fat diet did not reach the goal of reducing fat consumption to 20% (instead, reaching 24.5% and then rising to 29%), the results showed that women in the dietary intervention group who ended up developing breast cancer had lower mortality rates than the women in the control group.

Lead study author Rowan Chlebowski of the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center said the study highlights the importance of smart dietary choices. With obesity linked to at least 13 types of cancer including stomach, pancreatic, colorectal, and postmenopausal breast cancer, as well as heart disease and diabetes, keeping a healthy diet is key to overall health. “This is dietary moderation. It’s not like eating twigs and branches,” Chlebowski said. “It’s what people were eating, say, 20 years ago, before you could pick up 900 calories in one candy bar.”

Elisa Port, chief of breast surgery at Mount Sinai Health System in New York, who was not involved in the study, commented that the conclusions from the trial “are exciting and empowering for the patient. This is a wake-up call for women — there’s something they can do, rather than just waiting for the shoe to drop.”

Kathryn is a curious world-traveller interested in the intersection between nature, culture, history, and people. She has worked for environmental education non-profits and is a Spanish/English interpreter.